This invention relates generally to a meat recovery method and apparatus by which meats such as beef, pork and mutton non-connective tissues are mechanically separated from essentially flat bones, such as neck, back, rib, etc., without the total destruction of the bone. Coarse texture results in the tissues removed, such as 0.06 inch thick or greater having a low calcium content.
A known press for separating meat from bones generally comprises a cylindrical pressure chamber for containing a combination of meat and bones to be separated, a pressure piston slidable within the pressure chamber to exert pressure on the contents within the pressure chamber, a sealing wall for closing off the end of the pressure chamber opposite the piston when pressure is exerted by the piston, and a perforated lining sleeve within the pressure chamber, the piston extending into the sleeve for exerting pressure on the meat and bones within the pressure chamber to separate the meat and bone combination by forcing meat through the openings in the sleeve into a collector channel.
The meat recovered is generally in the form of a pasty mass due to the extreme pressure required for the separation process limiting the end use of the recovered meat slurry. Also, the elevated pressure applied by the pressure piston tends to totally destroy the bone giving rise to unacceptable calcium levels in the recovered meat.
A press of the foregoing type is disclosed in British Patent 1,563,750 and in U.S. Pat. No. 4,536,920 in which a perforated chamber liner is employed, the pressure piston filling the liner with a combination of meat and bones for separation by pressing. The sealing wall is retractable relative to the discharge end of pressure chamber such that a cake of crushed bone material may be removed.
U.S. Pat. Nos. 4,014,075 and 4,141,173 discloses similar presses for separating meat from bones except that the sealing wall is in the form of a slide valve having an opening which is laterally shifted into and out of axial alignment with the pressure chamber for opening and closing the chamber.
The meat recovered utilizing the known presses is not readily usable as a primary meat source. Moreover, some of the crushed bone tends to pass through the lining perforations together with the separated meat such that the recovered meat has an undesirable amount of bone marrow and a calcium content which affect the quality of the meat and could fail to meet industry and government standards.
The lining perforations, which are typically round holes provided in a liner sleeve, oftentimes clog with bone and sinew such that the press operation must be interrupted until the clogged liner is replaced with a clean liner, thereby leading to downtime losses in operation and requiring an inventory of clean liners for each given press operation.
Other disadvantages presented by the known meat recovery presses concern the sealing wall at that end of the pressure chamber opposite the pressure piston which exerts pressure against the meat and bone combination. The sealing wall is formed at the end of a hydraulic ram which must be retracted to open the chamber for expelling the crushed bone cakes, or is in the form a transversely slidable valve having a through opening which when shifted into axial alignment with the pressure chamber facilitates discharge of the crushed bone cakes.
With either arrangement the forced applied by the pressure piston must be relaxed when the sealing wall is open. This slows the meat recovery operation and, when the end sealing wall is mounted on a pressure actuated ram, adds to the floor space and equipment required for this purpose.